Interactive tools – Generate Input Files & Convert Parameters

Generate Input Files

This section provides an interface to generate custom .ini files by selecting the desired instrument and parameter values below.

⚠️ For now, only SCAO mode is available. Other modes coming soon.

.ini Parameter File Generator - For Available AO Instruments

Select instrument: ERIS_SCAO_NGSERIS_SCAO_LGSHARMONI_SCAO_NGSMICADO_SCAO_NGSSOUL_SCAO_NGSSPHERE_SCAO_NGS

NGS only system ✴️
HO part: Science - NGS

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[telescope]

Zenith Angle (degree): ℹ️ the angle between the telescope's pointing direction and the zenith

[atmosphere]

Seeing (arcsec): ℹ️ defined at Zenith ([Telescope] ZenithAngle = 0)

[sources_science]

Band: -- Select Band --J (1.20 µm)H (1.66 µm)K (2.10 µm)L (3.32 µm)M (4.78 µm)

Distance⁽¹⁾ (arcsec):

[sources_HO]

NGS Wavelength set at 750 nm | Band: I

Distance⁽¹⁾ (arcsec):

[sensor_HO]

V-Magnitude⁽²⁾:

NumberPhotons (nph/subaperture/frame):

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⁽¹⁾ Distance corresponds to the Zenith parameter in the[sources_science] section, and either the [sources_HO] or[sources_LO] section, depending on the system. ⚠️ It should not be confused with the ZenithAngle parameter in the [telescope] section, which... ▶ Show more

⁽²⁾ The calculation of the NumberPhotons parameter, along with a dedicated interface, is detailed here.

Conversion from Magnitude to Number of Photons per Subaperture per Frame

The value of the parameter NumberPhotons in (expressed in photons per subaperture per frame) for a natural guide star of a given magnitude is calculated using the following formula:

$$\text{NumberPhotons} = ZP \left(\frac{Tot_{throughput}}{Sensor_{framerate}}\right) \left(\frac{D^{2}-(D*ObscurationRatio)^2}{N_{lenslets}^2}\right) 10^{\textstyle -\frac{Mag}{2.5}}$$

Parameter definitions

	B band	V band	R band	I band	J band	H band	K band
$ZP$ (Zero Point) $(ph/s/m^2)$	$1.24e10$	$8.37e9$	$1.36e10$	$8.93e9$	$4.11e9$	$2.87e9$	$1.70e9$
$Tot_{throughput}$	$0.07$	$0.16$	$0.19$	$0.2$	$0.24$	$0.26$	$0.26$

Spectral band extinction correction

For a spectral class M0V star, the apparent magnitude is corrected by an extinction term that varies by band:

$$Mag = Mag_V + \text{extinction\_correction}$$

	B band	V band	R band	I band	J band	H band	K band
$\text{extinction\_correction}$	$1.37$	$0$	$-1.26$	$-2.15$	$-2.49$	$-3.03$	$-3.29$

This formula converts the visual magnitude, corrected for spectral band extinction, into the expected number of photons detected per subaperture per frame. It takes into account instrumental parameters such as the telescope’s effective collecting area, the number of wavefront sensor lenslets, the total system throughput, and the wavefront sensor's frame rate.

Below is an interactive interface that allows you to calculate the NumberPhotons TipTop parameter from a given magnitude for the selected instrument.

Conversion from Magnitude to Number of Photons

Select instrument: ERIS_SCAO_NGSERIS_SCAO_LGSHARMONI_SCAO_LGSMICADO_SCAO_NGSSOUL_SCAO_NGSSPHERE_SCAO_NGS

NGS only system ✴️
Number of lenslets: 40
Sensor frame rate: 1000 Hz

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[sources_HO]

NGS Wavelength set at 750 nm | Band: I

[sensor_HO]

V-Magnitude:

NumberPhotons (nph/subaperture/frame):